1. Field of the Invention
The present invention relates to a display-driving device and a display-driving method for driving a panel type display such as a liquid crystal display, a plasma display, and a display for displaying a picture image corresponding to an image signal on an optical waveguide plate by controlling leakage light at a predetermined position of the optical waveguide plate by controlling the displacement action of an actuator element in a direction to make contact or separation with respect to the optical waveguide plate in accordance with an attribute of the image signal to be inputted (conveniently referred to as “electrostrictive type display”).
2. Description of the Related Art
Those hitherto known as displays include display devices such as cathode ray tubes (CRT), liquid crystal displays, and plasma displays.
Those known as the cathode ray tube include, for example, ordinary television receivers and monitor units for computers. Although the cathode ray tube has a bright screen, it consumes a large amount of electric power. Further, the cathode ray tube involves a problem that the depth of the entire display device is large as compared with the size of the screen. Further, for example, the cathode ray tube involves drawbacks in that the resolution is decreased in the circumferential areas of the display images, the image or the graphic is distorted, there is no memory function, and it is impossible to present display in a large scale.
The reason for the foregoing phenomenon is as follows. That is, in the case of the cathode ray tube, the electron beam emitted from the electron gun is greatly deflected. Therefore, the light emission point (beam spot) is expanded at portions at which the electron beam reaches the fluorescent screen of the Braun tube in an inclined manner, and thus the image is displayed in an inclined manner. For this reason, strain occurs on the display image. Moreover, there is a limit for the maintenance to keep a large space at the inside of a Braun tube to be in a vacuum.
On the other hand, the panel type display, for example, the liquid crystal display is advantageous in that the entire device can be miniaturized, and the display consumes a small amount of electric power. The plasma display and the electrostrictive type display can be miniaturized, because the display section itself does not have a large volume, in the same manner as the liquid crystal display as described above. They are advantageous in that there is no trouble in viewing the screen, because the display surface is flat. Especially, the AC type plasma display and the electrostrictive type display are also advantageous in that the refresh memory is unnecessary owing to the memory function of the cell.